Studies on the pathology of bacterial kidney disease (Renibacterium salmoninarum) in coho (Oncorhynchus kisutch) and Atlantic salmon (Salmo salar)

With the intensification of the aquaculture industry along the west coast of Canada, there has been a concomitant increase in the prevalance of bacterial kidney disease (BKD) (Renibacterium salmoninarum)(Rs) in production and government hatchery facilities. Due to the paucity of information on the pathogenesis and epizootiology of Rs, treatment and control measures have been confounded and emergance of BKD exacerbated. Initially, to enhance specificity over conventional histochemistry for demonstration of Rs in histological sections an avidin biotin conjugated immunoperoxidase technique was developed for us to monitor the histopathological manifestation of BKD. To ascertain the temporal and spatial hlstogenesis of BKD. coho (Oncorhvnchus kisutch) and Atlantic (Salmo salar) salmon ware challenged experimentally by intraperitoneal injection and naturally by cohabitation with Rs-innoculated fish than serially sampled. Histopathology revealed lesions consistent with past case reports and investigations, as well as previously undescribed manifestations including, inflammatory call kinetics in the renal perivascular compartment, cresentic glomerulonephritis, extrarenal dissemination (via septic emboli or direct extension), and ovarian follicular cell accumulation of Rs. Pseudocyst formation, renal interstitial hyperplasia and meningoencephalitis were also characterized. The granulomatous response in coho salmon was predominantly histiocytic, whereas, in Atlantic salmon a tuberculoid response was more apparent. In either species a profound call mediated immunity was adduced. To further resolve the nature of the inflammatory response, coho and Atlantic salmon were immunosuppressed by administration of suprapharmacologic doses of glucocorticosteroids. On challange with Rs both species incurred an earlier onset and greater rate of mortality than immunocompetent cohorts. The granulomatous response appeared irregular and expansive with exuberent intra- and extracellular Rs growth. These observations may be attributed to inhibition of prostaglandin and leukotrienne synthesis, as well as an inability to immunologically prima phagocytes. To evaluate the inflammogenic potential o£ somatic, cell- wall associated, and soluble fractions of Rs, coho and Atlantic salmon were injected and serially sampled for histopathology. Past studies on Rs virulance determinants and pathogenic mechanisms have focused almost exclusively on a soluble protein, designated p57. In this investigation no histological alterations were appreciated in fish challenged with cell-wall associated or soluble (p57) fractions, however, mild, multifocal pyogranulomata were noted in the renal interstitium of coho and Atlantic salmon challenged with the somatic or peptidoglycan fraction of Rs. Peptidoglycans of a number of mammalian pathogens are strongly inflammogenic, poorly biodegradable, and persist in host tissue for protracted periods. Chemical resolution and in vivo evaluatlon of subcellular components of Rs is warranted to further resolve the pathogenesis of BKD in salmonid species

Paranannizziopsis spp. infections in wild snakes and a qPCR assay for detection of the fungus

The emergence of ophidiomycosis (or snake fungal disease) in snakes has prompted increased awareness of the potential effects of fungal infections on wild reptile populations. Yet, aside from Ophidiomyces ophidiicola, little is known about other mycoses affecting wild reptiles. The closely related genus Paranannizziopsis has been associated with dermatomycosis in snakes and tuataras in captive collections, and P. australasiensis was recently identified as the cause of skin infections in non-native wild panther chameleons (Furcifer pardalis) in Florida, USA. Here we describe five cases of Paranannizziopsis spp. associated with skin lesions in wild snakes in North America and one additional case from a captive snake from Connecticut, USA. In addition to demonstrating that wild Nearctic snakes can serve as a host for these fungi, we also provide evidence that the genus Paranannizziopsis is widespread in wild snakes, with cases being identified in Louisiana (USA), Minnesota (USA), Virginia (USA), and British Columbia (Canada). Phylogenetic analyses conducted on multiple loci of the fungal strains we isolated identified P. australasiensis in Louisiana and Virginia; the remaining strains from Minnesota and British Columbia did not cluster with any of the described species of Paranannizziopsis, although the strains from British Columbia appear to represent a single lineage. Finally, we designed a pan-Paranannizziopsis real-time PCR assay targeting the internal transcribed spacer region 2. This assay successfully detected DNA of all described species of Paranannizziopsis and the two potentially novel taxa isolated in this study and did not cross-react with closely related fungi or other fungi commonly found on the skin of snakes. The assay was 100% sensitive and specific when screening clinical (skin tissue or skin swab) samples, although full determination of the assay’s performance will require additional follow up due to the small number of clinical samples (n = 14 from 11 snakes) available for testing in our study. Nonetheless, the PCR assay can provide an important tool in further investigating the prevalence, distribution, and host range of Paranannizziopsis spp. and facilitate more rapid diagnosis of Paranannizziopsis spp. infections that are otherwise difficult to differentiate from other dermatomycoses

Best practice guidelines for cetacean tagging

Animal-borne electronic instruments (tags) are valuable tools for collecting information on cetacean physiology, behaviour and ecology, and for enhancing conservation and management policies for cetacean populations. Tags allow researchers to track the movement patterns, habitat use andother aspects of the behaviour of animals that are otherwise difficult to observe. They can even be used to monitor the physiology of a tagged animal within its changing environment. Such tags are ideal for identifying and predicting responses to anthropogenic threats, thus facilitating the development of robust mitigation measures. With the increasing need for data best provided by tagging and the increasing availability of tags, such research is becoming more common. Tagging can, however, pose risks to the health and welfare of cetaceans and to personnel involved in tagging operations. Here we provide ‘best practice’ recommendations for cetacean tag design, deployment and follow-up assessment of tagged individuals, compiled by biologists and veterinarians with significant experience in cetacean tagging. This paper is intended to serve as a resource to assist tag users, veterinarians, ethics committees and regulatory agency staff in the implementation of high standards of practice, and to promote the training of specialists in this area. Standardised terminology for describing tag design and illustrations of tag types and attachment sites are provided, along with protocols for tag testing and deployment (both remote and through capture-release), including training of operators. The recommendations emphasise the importance of ensuring that tagging is ethically and scientifically justified for a particular project and that tagging only be used to address bona fide research or conservation questions that are best addressed with tagging, as supported by an exploration of alternative methods. Recommendations are provided for minimising effects on individual animals (e.g. through careful selection of the individual, tag design and implant sterilisation) and for improving knowledge of tagging effects on cetaceans through increased post-tagging monitoring.Publisher PDFPeer reviewe

A new perspective in bio-refining : Levoglucosenone and cleaner lignin from waste biorefinery hydrolysis lignin by selective conversion of residual saccharides

An unexpected opportunity is reported to improve the sustainability of biorefineries whereby 8 wt% levoglucosenone (LGE) can be derived from unconverted saccharides in a lignin-rich biorefinery waste stream in a highly selective fashion (>90%). Additionally, in the process a purer lignin is obtained which can be used for further processing or materials applications. LGE is a valuable and versatile product with a plethora of applications

Landscape Ecotoxicology of Coho Salmon Spawner Mortality in Urban Streams

In the Pacific Northwest of the United States, adult coho salmon (Oncorhynchus kisutch) returning from the ocean to spawn in urban basins of the Puget Sound region have been prematurely dying at high rates (up to 90% of the total runs) for more than a decade. The current weight of evidence indicates that coho deaths are caused by toxic chemical contaminants in land-based runoff to urban streams during the fall spawning season. Non-point source pollution in urban landscapes typically originates from discrete urban and residential land use activities. In the present study we conducted a series of spatial analyses to identify correlations between land use and land cover (roadways, impervious surfaces, forests, etc.) and the magnitude of coho mortality in six streams with different drainage basin characteristics. We found that spawner mortality was most closely and positively correlated with the relative proportion of local roads, impervious surfaces, and commercial property within a basin. These and other correlated variables were used to identify unmonitored basins in the greater Seattle metropolitan area where recurrent coho spawner die-offs may be likely. This predictive map indicates a substantial geographic area of vulnerability for the Puget Sound coho population segment, a species of concern under the U.S. Endangered Species Act. Our spatial risk representation has numerous applications for urban growth management, coho conservation, and basin restoration (e.g., avoiding the unintentional creation of ecological traps). Moreover, the approach and tools are transferable to areas supporting coho throughout western North America

Studies on the pathology of bacterial kidney disease (Renibacterium salmoninarium) in coho (Oncorhynchus kisutch) and Atlantic salmon (Salmo salar)

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The Heart of the Killer Whale: Description of a Plastinated Specimen and Review of the Available Literature

The killer whale (Orcinus orca, Linnaeus, 1958) is the largest extant delphinid. Despite its worldwide distribution in the wild and in dolphinariums, its anatomy remains relatively poorly described. In the present study, we describe the detailed morphology of a plastinated killer whale heart. The gross description of the arteries and veins reaching the organ and its coronary vessels are reported. Additional endoscopy and CT (computed tomography) scanning were performed to provide extensive measurements of its parts. In many aspects, the killer whale heart conformed to other delphinid heart descriptions, including position, relative size and shape and specific features such as extensive papillary muscles, trabecular endocardium and trabecula septomarginalis. These characteristics are representative of the delphinid family, suggesting that its functions and capacities are similar to that of other, smaller, dolphins and help understand the conditions in which these predators exert their remarkable physical performance necessary for their survival